def f(input1):
  if input1 >= 30:
    return 'Yes'
  return 'No'

if __name__ == "__main__":
  input1 = int(input())
  print(f(input1)) def f(input1):
  if input1 >= 30:
    return 'Yes'
  return 'No' f if input1 >= 30:
    return 'Yes'
   input1 >= 30 input1 30 return 'Yes' 'Yes' return 'No' 'No' input1 input1 if __name__ == "__main__":
  input1 = int(input())
  print(f(input1)) __name__ == "__main__" __name__ "__main__" input1 = int(input()) input1 int(input()) int input() input print(f(input1)) print f(input1) f input1 input1 = int(input()) int(input()) input1 def f(input1):
  if input1 >= 30:
    return 'Yes'
  return 'No' def f(input1):
  if input1 >= 30:
    return 'Yes'
  return 'No' f
def f(input1):
  if input1 >= 30:
    return 'Yes'
  return 'No'

if __name__ == "__main__":
  input1 = int(input())
  print(f(input1))